1. Field of the Invention
This invention relates to a configured contour measuring apparatus for measuring the surface contour in a predetermined cross-section of an object to be measured.
2. Description of the Prior Art
The conventional configured contour measuring apparatus (contracer) is of such an arrangement that a fulcrum is provided at the intermediate portion of an arm, a proving needle referred to as a stylus is secured to one end of the arm, a balancer weight is secured to the other end of the arm, the stylus is made slightly heavior in weight than the balancer weight so as to make the stylus touch the surface of an object to be measured, said arm is axially moved, whereby the movement of the stylus tracing the surface countour is measured by a differential transformer secured to the arm; and signals sent from said differential transformer are transimitted to a recorder to make same draw a figure, whereby the configured contour of the object to be measured is measured. However, in the conventional configured contour measuring apparatus as described above, a figure is recorded by the so-called analogue values, and hence, it is necessary to read the contour as digital values by further use of some measuring apparatus. From the above reasons, there have been such disadvantages that not only the measurement is troublesome but also some errors tend to be added in converting to the digital values, hence to decrease the accuracies in the contour measurement. Therefore, necessity has been voiced for development of a configured contour measuring apparatus capable of directly reading the digital values.
To meet the necessity, there has been proposed a configured contour measuring apparatus of said arm-type wherein an A/D converter is additionally provided, so that the digital values can be directly read. However, said measuring apparatus substantially measures the analogue values, and consequently, said disadvantages have not been obviated. Furthermore, there has been proposed a configured contour measuring apparatus of the type wherein a linear scale consisting of a calibrated glass bar is secured to an arm of an arm-type configured control measuring apparatus, an index scale is provided in opposed relationship with said linear scale, and measurement is made on the movements of said both scales. However, in that case, errors due to the circularly arcuate motion of the arm should be unavoidable, and any satisfactory configured contour measuring apparatus has not been obtained at all.